I. Field of the Invention
The present invention relates generally to turbine engines and more particularly to a turbine engine construction having a hollow shaft through which fuel is delivered and pumped into the combustor chamber of the turbine engine.
II. Description of the Prior Art
In turbine engine constructions, it is well known that fuel pumps are used to direct a fuel into the combustor chamber of the turbine engine. Typically, the fuel pumps are driven by the turbine engine by means of an accessory gear box or other means for coupling the pump to the engine shaft. However, the weight and complexity of the drive mechanism substantially increases the size and bulk of the turbine engine. Moreover, energy losses caused by these mechanisms further decrease the efficiency of the turbine engine. Moreover, the numerous parts in the drive mechanisms are subjected to wear and require lubrication, periodic maintenance and repair.
Of course, it has also been known to use electric motors for driving the pumps but such motors require a separate or engine driven power source for actuating the motor to drive the pump. Moreover, size and weight of these motors can significantly affect the breadth or size of the turbine engine since they are often mounted to the turbine housing in close proximity to the pump. Moreover, regardless of the means used for driving the pump, the pump must provide sufficient pressure levels to overcome the system friction losses within the fuel passageways and sufficient pressure to inject the fuel into the combustor chamber against the force of the pressure caused by combustion within the combustor chamber. Since pressure requirements tend to increase the size and complexity of the previously known fuel pumps.
In addition, although it has been known to provide a fuel passageway through the center of the turbine shaft so that rotation of the shaft imparts a centrifugal force to the fluid to drive it outwardly from the center of the shaft, such fluid systems primarily rely on the pressure provided by a turbine driven pump to overcome the friction losses on the fuel passage and to overcome the pressure in the combustor chamber. As a result, previously known turbine shaft fuel supply systems do not supplant the need for powerful pumps and drive mechanisms and the problems inherent with those devices.